I don't really want two plugins that do almost the same thing. At the same time, I don't want to have a check for the old configuration on every run either. Although I was making it more complicated than it had to be. I'll just add an upgrade routine the moves existing configurations over to the new one.

I've created a patch to add the import fields as checkboxes and default to `all fields` if no fields are checked. It needs a bit of testing but its a start.
The reason I've implemented this differently is I want to import all the fields but only test uniqueness on some of them (as some source fields change when they shouldn't).